This application relates to tunable lasers, and in particular, to tuning of the laser wavelength in actively mode-locked lasers.
Actively mode-locked lasers may include a laser cavity enclosing a laser gain medium to produce laser oscillation and an intra-cavity optical modulator to lock different laser modes supported by the laser cavity in phase to produce laser pulses. Such lasers may be designed to produce high-quality short optical pulses at a very high bit rate such tens of GHz or higher for various applications, including fiber communication systems.
Various applications may require the laser wavelength of a laser to be at a specific wavelength. In optical wavelength-division-multiplexed (WDM) systems, for example, the signal wavelengths of different optical WDM channels need to be at designated WDM standard wavelengths according to a wavelength standard such as the WDM wavelengths established by the International Telecommunication Union (ITU). This application provides techniques for tuning the laser wavelength of actively mode-locked fiber lasers from one desired laser wavelength to another and for dynamically locking the laser at a particular laser wavelength against drift or fluctuation in the laser wavelength.